How did the Brexit referendum — a vote about the UK’s status in the European Union — become the catalyst for abuse against Polish nurses and British citizens of Pakistani background? Social media can’t tell us much about this: Twitter’s conversation analysis post-Brexit indicated that the economy was by far the most discussed topic for the referendum. Yet polling firm Ipsos Mori noted that immigration had replaced the economy as the single most important factor driving the Leave vote in the final weeks beforehand. The true debate on the referendum, then, played out not on social media but in offline conversations and traditional media, and as such serves as a reminder that, despite its seeming primacy, social media is only a subset of the much larger world.

Polling data reveal a particularly interesting fact about that world: Those who voted Leave had the least exposure to migrants, while those with the most exposure to them were most likely to vote Remain. It was fear of immigration, not immigration itself, which led the Leave camp to victory — not the reality of migrants, but the idea of them. Where did this idea come from? What concentrated the minds of Leave voters?

The two major players involved in the Leave campaign were the UK Independence Party (UKIP) and Vote Leave. The rhetoric of their movement has been widely criticized as racist and deceptive on the facts of immigration. But the problem with their rhetoric can be expanded. The philosopher Jennifer Saul has talked about how the linguistic drift of increasingly intolerant speech can lead to racist violence. As we become habituated to a subject of speech, our standard of what is acceptable to say (or not say) shifts, which in turn opens up possibilities for how we may act.

Saul introduces the concept of the “figleaf,” which differs from the more familiar dog whistle: while the dog whistle targets specific listeners with coded messages that bypass the broader population, the figleaf adds a moderating element of decency to cover the worst of what’s on display, but nevertheless changes the boundaries of acceptability. The example Saul uses to illustrate the idea is Donald Trump’s infamous description of Mexican immigrants to the US “bringing drugs. They’re bringing crime. They’re rapists” — and then he introduces his figleaf, the “get-out” clause: “And some, I assume, are good people.” This concept seems relevant to the Leave campaign and the recent outbreak of racist behavior in the UK.

Rhetoric extends to visual print strategies, and those of the Leave campaign are worth examining. UKIP was roundly condemned for its “Breaking Point” billboard, which shows a large queue of brown-skinned migrants stretching beyond the picture frame. The implication is that they are coming to British shores: “We must … take back control of our borders.”

The “Breaking Point” billboard is profoundly deceptive: The photograph is of migrants moving from one border to another in Slovenia, not coming to the UK. But its intention was not to be journalistically accurate; it was meant to evoke fear, specifically of an uncontrollable mass of people. In this it is strikingly similar to Nazi propaganda, with which it was quickly compared. It should not escape the reader that the people in the billboard are all brown-skinned. This is not coincidental: there is in fact a pale figure in the bottom right, but his presence has been obscured by the “Leave the European Union” banner. He has been effectively erased. To be clear, the people moving into and across the European Union include those of many different ethnicities, but the image here reduces the larger complexity, homogenizing the mass into a gigantic, monolithic Other.

One might think that UKIP is an easy target for criticism: Several of its candidates and supporters are well known for having used a wide variety of racist and homophobic slurs. But the official Vote Leave camp also produced imagery clearly intended to stir up anxiety about immigration, and I would argue that it shares responsibility for the rise of hate crimes. Consider the following:

This first Vote Leave graphic was distributed on a flyer and placed in millions of homes across the UK — an example of old-school, forced virality. It’s also an example of pointed, deceptive data visualization, even though it looks straightforward.

It has a title (“Countries set to join the EU”), a key for countries too small to have their names imprinted directly on the map, numbers for those countries, and population levels. There is a map of the EU, represented in several shades of gray. The UK is rendered in black, the countries numbered 1–5 are rendered in red, and there are two extra countries rendered in salmon. What’s wrong? What could be more objective than a map with a key?

The deception, however, goes farther. By the coloring of the countries and the key, the graphic implies that the countries rendered in color are the ones joining the EU. Syria and Iraq are colored but not placed in the key. They are not discussed in the flyer’s accompanying text, and that’s because they’ve not applied to join. What are they doing there? They are highlighted merely to spotlight the proximity of warzones to countries that have applied to the EU: it’s guilt — and fear — by association.

The graphic contributes to heightened anxiety over the applicant countries, and it increases the number of countries on the map with predominantly Muslim populations. It blocks them all together and emphasizes their Otherness. But the campaign provides itself with a form of plausible deniability by coloring Syria and Iraq somewhat differently. To return to Saul, this is the fig leaf that gives the Leavers the space to present something with xenophobic overtones but still deny charges of racism. Some noted the deception at play in this graphic, but one wonders how many viewers would have taken the time to understand the intricacies.

A second graphic from the Leave campaign — another flyer, readily available from its website — is even more pointed.

This time there is virtually no difference in color between countries they claim are “set to join” the EU (such as Turkey) and one that has nothing to do with the EU (Iraq). Syria is also highlighted, albeit in a slightly different shade, but the suggestion that it may also be set to join is there (again, it’s not).

What’s more, the graphic doesn’t simply imply that the populations of these countries will soon enter the EU. The figures of people concentrated in this area are all pointed, with a massive, gradient-hued arrow, toward the UK. The imagery is strongly reminiscent of one of the original forms of data visualization: battlefield maps. An arrow is just as much a part of the visual language of invasion as a photograph of a lengthy queue of people who look different from “us.”

Can we draw a connection between the now-clear intent of these graphics and those who voted to leave the EU? We can, to some extent, although the precise nature of such connections is impossible to pin down. Images are never created in a vacuum; they are products of the society in which they are made. These images were produced in an environment where the government itself distributed posters telling undocumented immigrants to “go home” and newspapers fanned racist sentiment, even thoughthese subjects had little to do with the true substance of the Brexit vote: the UK’s economic and political status in Europe. The Leave campaign’s images bolstered a larger rhetorical strategy in the media that included prints ads, social media, television ads, politicians’ speeches, and other methods. All of it obscured basic economics while tapping into fears about immigration. The day after the referendum, Channel 4 journalist Ciaran Jenkins interviewed a man on the street who provided an explanation for his Leave vote that’s not at all far from the invasion-style graphic. Here’s the exchange:

Man: “It’s all about immigration. It’s not about trade or Europe or anything like that, it’s all about immigration. It’s to stop the Muslims coming into this country. Simple as that.” Jenkins: “Do you think you voted to leave the EU to stop Muslims coming to the country?” Man : “To stop immigration.” Jenkins: “Right.” Man: “The movement of people in Europe, fair enough. But not from Africa, Syria, Iraq, everywhere else — it’s all wrong.”

Does this mean that everyone who voices concerns about immigration is racist? Of course not. A number of people who voted to leave had legitimate worries — many come from communities with precarious and hard-won legal and economic statuses, and they wanted to protect those achievements because they felt them vulnerable.

But it’s undeniable that much of the Leave campaign platform was built on deceptions, outright lies, and xenophobia. Some people voted emotionally; others voted based on that deception. Due to imagery depicting immigrants as a collective invasion force, it’s no surprise that both groups voted as they did. Imagery can be an agent of habituation, contributing to our perceptions alongside other speech acts. With their virtually imperceptible figleaves, images shift the boundaries of acceptability little by little, until suddenly we find ourselves in a situation where fellow citizens are told to “go back home” based upon the color of their skin.